The present invention relates to an apparatus and method for separating adjacent objects on a conveyor. More particularly, the present invention is directed to a conveyor system which is capable of expanding a distance between two adjacent objects while moving the objects from one conveyor to another.
Separator conveyors are used to separate objects on a moving conveyor line. Usually, objects to be conveyed from one point to another in a manufacturing line are fed to a conveyor which moves the objects throughout the line. Generally, objects are fed in bulk to a conveyor line. The objects may be fed through a combining apparatus which aligns the objects in single file. Such a device is illustrated for example in U.S. Pat. No. 4,544,059. After the single file line of objects is formed, the objects tend to remain in line, against one another. Depending on the manufacturing line, a spacing may be desired between adjacent objects in order to carry out certain screening, inspection or other operations on each object. If the objects are too close together, an operation being performed on one object may interfere with an operation being performed on an adjacent object. Accordingly, it is important to control spacing of adjacent objects on the conveyor line.
In certain known separation conveyors, a mechanical device physically separates adjacent objects. For example, U.S. Pat. Nos. 1,689,247 and 1,463,527 disclose serpentine conveyor systems wherein a rotating drum having pins or fingers physically separate objects as they pass around the drum on the conveyor belt.
U.S. Pat. No. 3,386,558 discloses a feeder mechanism in which a device having fixed, radially extending arms is cam driven so that, as the device rotates, pneumatic suction cup gripping means at the ends of the arms travel along a path for removing folded carton blanks from a hopper and depositing them atop stacked containers moving along a conveyor belt. Rotationally eccentric movement is provided to the means which carries the fixed arms thereon.
U.S. Pat. No. 3,834,522 shows a transfer machine comprising a turret having a plurality of radially translatable carriages mounted thereon, which carriages are fitted with a suction cup for gripping a container. A cam track moves the carriages radially outwardly during rotation so as to enable the suction cups to grip the container at the unloading station, then retracts radially inwardly for transporting the container, and then moves radially outwardly to feed the container into the stacking device. The turret provides for intermittent movement between the stations to allow sufficient dwell time for the freshly printed containers to dry.
U.S. Pat. No. 4,369,875 discloses a slightly different arrangement wherein a series of pins is rotatingly maintained on a separate endless belt conveyor. The endless belt conveyor is driven at approximately the same rate as the feed conveyor. As objects pass the endless belt conveyor, the pins are inserted between adjacent objects thereby spreading the distance between those objects.
U.S. Pat. No. 4,726,876 discloses an apparatus for changing the spacing between articles of a moving array of discrete articles, and includes transfer means mounted for orbiting along a closed orbital path passing through a receiving zone and a discharge zone. The orbital radius of the transfer means is adjustable to provide an orbital radius in the discharge zone which is different from that in the receiving zone. The transfer means are maintained in fixed, equal angular distances between them along the orbital path whereby the orbital path distance between adjacent transfer means is different in the discharge zone from that in the receiving zone thereby resulting in a different spacing between adjacent articles in the discharge zone from that in the receiving zone. Two or more orbital spacer means may be utilized in tandem to provide the change in spacing in stages.
Other types of mechanically operated systems are also known. In each case, a device is generally engaged between adjacent objects to force the objects apart. There are several problems associated with these types of systems. Because the separator is an independently driven device, it must be controlled separately. The separate control system can be expensive and if the system breaks down, separation cannot be maintained. Yet further, the known techniques of separation require insertion of a device between adjacent objects. If the objects are fragile, they may be easily broken or damaged by insertion of the separating device. In addition, the physical touch may cause dirt or other unwanted contamination. The shape of the objects may render this approach unworkable.
The present invention is used to separate adjacent objects on a conveyor line so that certain manufacturing operations can be performed on the objects, while at the same time avoiding the problems associated with the prior known techniques of separation.
It is, therefore, an object of the present invention to provide a separating conveyor system which is free of the aforementioned and other such disadvantages wherein adjacent objects on a moving conveyor can be spaced from one another without the use of independent separating devices.
To achieve these and other advantages, the present invention is a conveyor arrangement, which accelerates and separates adjacent objects. The separation is accomplished with minimal contact and without interposing any separating means or devices. It requires little or no adjustment to work with a variety of shaped and sized objects.
The conveyor arrangement uses at least two so-called sideflexing conveyor chains arranged side-by-side similar to the conveyor chains shown in U.S. Pat. Nos. 4,823,939 and 5,779,027. This type of conveyor comprises flat topped links, which present an approximately continuous moving surface to the objects being conveyed.
The invention includes an area of the conveyor where two such chains are moving in a curve and are adjacent and parallel.
The objects to be conveyed and separated are introduced in single file on the first chain, and are riding near one margin of the chain. When the chain enters the curve, the ends of the links where the objects are riding accelerate and separate. Each conveyor section includes a plurality of links. Each link tapers from its mid-section toward each end. When the chain enters a curve the taper allows the spaces between links to close without interference on the side toward the center of curvature and to open on the opposite side. Objects are placed onto the idle end of the first conveyor, The guide rail crowds the objects toward one edge of the conveyor.
The objects are transferred from the first chain to the second chain in the curve, by a guide rail. They are now riding on the margin of the second conveyor. When the second conveyor leaves the curve and enters a straight, the link ends separate and accelerate, further separating the objects. The second chain is driven at a higher speed than the first chain. The linear velocity of the edge of the first chain at the outside of the curve is increased in consequence of the curvature and the linear velocity of the edge of the second chain at the inside of the curve is reduced in consequence of the curvature. The speeds of the chains are adjusted so the adjacent edges of the two conveyors along the curve are approximately the same. It is understood that "linear velocity" refers to the time rate of change of position of a body.
In an advantageous embodiment of the invention, the second chain enters a curve in the opposite direction, further accelerating and separating the objects. In this curve the objects are transferred to the third chain and the transfer and acceleration occurs, and when the third chain enters a straight-line section, the objects are again accelerated and separated. The process is same as transfer from first chain to second, and constitutes a second stage of the same process.